Luminescent tube and process of manufacturing same



Patented June 6, 1933 UNITED STATES FREDERICK W. 20178,

PATENT OFFICE 01' NEW YORK, N. Y.

t'l'o Drawing. Application filed Kay 81,

In m copendin ap lication, Serial No. 339,735 I have desc ibecfandclaimed a process of cleaning up water vapors in a luminescent tube. Asis there made clear, this im- 5 purity even when too slight in amount toaffect the color of the luminous atmosphere within thetube,'nevertheless attacks the material of the electrode and causesrapid blackenin of the glass of the tube. The said copen mg a plicationdescribes and claims a method of disposing of the water vapor whichconsists in first suppl in an additional uantity of oxygen to ma e 1tcertain that a l the hydrogen resent will combine with such oxygen toorm water va or and then to dispose of the water vapor y roviding amaterial that has a strong a nity for water vapor. The materialspecified in the aforesaid application is phosphoric anhydride.

The present invention is a s ecific chan e in the invention describedand c aimed in said application; I have found that a number of metallicoxides have such a strong aflinity for water vapor that they may be usedwith ad- 95 vantage to take up the water vapor which forms a very activeand deleterious element in a luminescent tube. Such oxides indeed haveso pronounced an aflinity for water vapor that it is not practicable tointroduce them into the tube as oxides for the reason that while theyare exposed in the open air they are likely to take up "so much watervapor as to lose their effectiveness. when introduced into the tube:

By the method of the present invention I introduce metallic compoundsinto the tube and so treat them when in place that they form or may bereduced to the oxides. As

' exam les of the metallic compounds which I have ound efiective toaccomplish the object of the present invention, I may enumerate amongothers, barium nitrate Ba(NO,) barium nitrite, Ba(NO,') potassiumnitrate KNO,. An aqueous solution of these materials may be formed anddropped in suflicient uantity, preferabl within the electrode 0 amber orat any ot er lace that may be desired within the tube. are, however,should be taken not to place the solution 11 on the electrode itself asthe resulting o'xi e pro- 1829. Serial 1T0. 864,947.

duced therefrom will suffer in etficienc when hot. When this solutionhas dried, it is heated in any convenient manner to decompose the same.It is to be observed that when the initial metallic compound from whichthe solution is made contains oxygen, the decomposition is not effecteduntil the tube is exhausted.

From the compoundsabove mentioned upon decomposition effected in themanner above described, there would remain within the tube barium oxide(BaO) potassium oxide K 0 or the like.

I may, also, instead of introducing the compound in an aqueous solution,introduce it in an other convenient manner as for instance, ln solidform. It will be obvious also, that my invention is capable of manyvariations without departing from the scope thereof and I include allsuch variations as part thereof.

What I claim is 1. The process of removing water vapor from aluminescent tube which consists in introducing into said tube duringmanufacture, but not on the electrodes, 8. heat decomposable nitroen-oxygen salt of an alkali or alkaline eart metal; and heating saidtube and said salt during the manufacture of the tube and converting thesalt into the oxide of said alkali or alkaline earth metal.

2. The process'of removing water vapor from a luminescent tube whichconsists in introducing into said tube during manufacture but not on theelectrodes, barium nitrate; an heatin said tube and said salt during themanu acture of the tube and converting the salt into an-oxide of barium.

In witness whereof, I have set my hand hereto this 26th day ofApril,-1929.

FREDERICK W. ZONS.

